Operatively-excised purely regurgitant mitral valves in 108 patients aged 21-73 years (mean 55) (63% men) undergoing isolated mitral valve replacement were examined for calcific deposits. Of the 108 patients, 19 (18%) had leaflet and/or chordal calcific deposits, but in each the deposits were small and did not appear to alter mitral function. Of the 19 patients with mitral calcium, 6 had had active infective endocarditis and the calcium likely represented healed vegetations: in 6 other patients, the leaflet calcium had extended from the mitral anulus in the setting of mitral valve prolapse. The average total serum cholesterol levels were higher in the patients with compared to those without mitral calcium. Thus, calcium deposits are relatively infrequent in adults with clinically isolated pure mitral regurgitation and when they occur, the deposits are small and in themselves do not appear to contribute to mitral dysfunction.